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Old 11-07-2013, 07:50 AM   #1
szboardstretcher
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QEMU and kernel testing


So I have some custom kernels I need to build and such, and QEMU is the preferred method of testing them.

When using QEMU though, there is no scroll back to the "dmesg" output. And obviously I cant grab the dmesg file after. Also, none of the redirection methods, including TCP, telnet, file, or anything actually put this output into a file.

So. How do I get ALL of the text output from QEMU into a file to debug? OR, how do you kernel experts debug things like this in QEMU?
 
Old 11-07-2013, 12:54 PM   #2
dyasny
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normally, you would ssh into the VM and pipe dmesg into less
 
Old 11-10-2013, 02:25 PM   #3
szboardstretcher
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Quote:
Originally Posted by dyasny View Post
normally, you would ssh into the VM and pipe dmesg into less
Im not following.

If I compile a new kernel and intramfs and boot them up in QEMU, and the kernel crashes halfway through the bootup,.. how am i supposed to SSH to the instance?

I was hoping to find a way to catch all of the kernel text output from start to crash from QEMU. How do kernel/qemu people go about doing that? Because I cannot find the documentation to explain how to do that!
 
Old 11-10-2013, 04:58 PM   #4
dyasny
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I thought you meant running the actual build process under QEMU. I'd try to use the qemu-monitor console if I were you:
http://stackoverflow.com/questions/1...-host-terminal
 
Old 11-13-2013, 06:29 AM   #5
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You could send your boot messages to a serial device and monitor the serial console of qemu on your host.
 
  


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